Method for operation of a multiple-membrane pump

ABSTRACT

A multiple-membrane pump deviates from synchronized operation. By completely uncoupled operation of the pump parts, it is possible to implement a metering pump using a single pump, in which all the parts pass through unequal conveying amounts, so that a predeterminable mixture can be produced.

CROSS REFERENCE TO RELATED APPLICATIONS

Applicant claims priority under 35 U.S.C. § 119 of German Application No. 10 2018 110 918.0 filed May 7, 2018, the disclosure of which is incorporated by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method for operation of a multiple-membrane pump, which has a pump housing having multiple membrane chambers accommodated in parallel line sections, which chambers are enclosed, in each instance, between multiple ball valves that close in the same flow direction, and divided, in fluid-tight manner, into a liquid chamber and an air chamber, in each instance, by a membrane, and wherein at least one drive is furthermore assigned to the pump housing in a drive chamber disposed between the air chambers, wherein the drive has drive means that are mechanically connected with the membranes, for moving the membrane between two movement end points, in each instance, independently of one another, and the drive means of the two membranes are asynchronously moved by the at least one drive.

2. Description of the Related Art

Such a solution with regard to precisely two membranes is already known from DE 10 2016 121 333 A1. Further prior art is evident from U.S. Pat. No. 4,718,832 A and US 2012/0063924 A1.

Dual-membrane pumps have already been known for a long time in the state of the art. They are known for transporting even difficult material to be conveyed, and are based on the fact that two membranes in membrane chambers that lie opposite one another alternately fill a liquid chamber in a suction movement and empty it in a pressure movement. In this regard, ball valves ensure a predetermined conveying direction, in that they block the inflow side during the pressure movement and the outflow side during the suction movement. In this regard, the membranes are coupled using a rigid connection shaft, and therefore move in push-pull mode.

The state of the art preferably provides for activation of the membranes using compressed air. A compressed-air connector is provided in a central chamber, by way of which connector compressed air is introduced into a first membrane chamber. The membrane chambers are divided into an air chamber and a liquid chamber by the membrane, wherein the compressed air flows into the air chamber and compresses the liquid chamber, and thereby the liquid is pressed out of the liquid chamber. In this regard, the membrane moves away from the opposite chamber, but, because of the connection using the connection shaft, takes the opposite membrane along with it and will compress the air chamber but expand the liquid chamber, and thereby exert a suction effect on the inflow. At the outermost point, an air distributor changes the air direction, and the air is introduced into the opposite air chamber, which has just been emptied, and the membranes move in the opposite direction, in coupled manner.

It is true that a known method from FR 54 797 E 1 supplementally provides that the two membranes are not connected with one another directly, but rather separately, by themselves, but are nevertheless operated synchronously to one another.

Such a method, however, whether with separate or through-connected membranes, brings about the result that the membranes always move in push-pull mode, and consequently also move the same conveying amounts.

SUMMARY OF THE INVENTION

Against this background, the present invention is based on the task of proposing a method for operation of a multiple-membrane pump, in which adapted use of a multiple-membrane pump, in particular also as a metering pump, is made possible.

These and other objects are accomplished by means of a method for operation of a multiple-membrane pump in accordance with the characteristics of the invention. Practical further developments of such a method for operation of a multiple-membrane pump are discussed below.

According to the invention, it is provided that a multiple-membrane pump has a structure extensively as previously known with regard to the dual-membrane pump from the state of the art. It comprises a pump housing having multiple parallel line sections, which each form a membrane chamber. In the membrane chambers, there is a membrane, in each instance, which divides the membrane chamber, in liquid-tight manner, into a liquid chamber and an air chamber. Only the liquid chamber can be reached by way of the line sections, and it is delimited, in the inflow and outflow side, by means of ball valves.

The invention now provides that instead of the mechanism operated with compressed air, a drive chamber is provided between the membrane chambers, in which drive chamber one or more drives and drive elements connected with it are accommodated for mechanical action against the membranes. The drive means are moved back and forth between two movement end points by means of the mechanical force of the at least one drive, and in this regard take the membranes along with them, so that at first, fundamentally the same movement sequence occurs as in the known dual-membrane pump in the state of the art.

The difference, however, consists in that the at least one drive is now operated in such a manner that the two or more membranes are now operated not in push-pull mode, but rather independently of one another. In this way, it is now possible to bring the output lines of the multiple-membrane pump together and to use this pump as a metering pump, in which an adjustable stream of a second, third or further media is added to a stream of a first medium.

In a first variant of the invention, this result can take place by way of the use of multiple drives in the drive chamber, which can be controlled by way of a common process controller, for example. In this case, each drive would excite the membrane connected with it to perform stroke movements, in accordance with the control commands of the process controller. The amount of medium conveyed by the pump section affected by it is dependent on the stroke frequency.

Alternatively, however, the drive means can also be connected with the same drive, by way of different gear mechanisms. As long as the gear mechanisms are unchangeable, in this regard, the conveying ratio is also always the same, at the same time. In this case, nevertheless, an adjustable conveying ratio could be achieved with only one drive, by means of adjustable gear mechanisms.

With regard to the drives used, different solutions can be utilized; in particular, electric motors, hydraulic or pneumatic cylinders or compressed-air valves can be used as drives.

What has been described above is therefore a method for operation of a multiple-membrane pump, which provides for asynchronous control of the two membranes and therefore makes it possible to use a multiple-membrane pump as a metering pump. 

What is claimed is:
 1. A method for operation of a multiple-membrane pump comprising: (a) providing the multiple-membrane pump, the multiple-membrane pump comprising a pump housing having a plurality of membrane chambers accommodated in parallel line sections, wherein each chamber is enclosed between a plurality of ball valves that close in an identical flow direction and is divided, in fluid-tight manner, into a liquid chamber and an air chamber by a respective membrane, and wherein at least one drive is assigned to the pump housing in a drive chamber disposed between the air chambers, wherein the at least one drive has drive elements mechanically connected with the membranes for moving the membrane between first and second movement end points independently of one another, and the drive elements are asynchronously moved by the at least one drive; and (b) operating the multiple-membrane pump to move the drive elements using the drive by way of adjustable gear mechanisms so as to achieve an adjustable conveying ratio.
 2. The method for operation according to claim 1, wherein the multiple-membrane pump is a dual-membrane pump having two membranes.
 3. The method for operation according to claim 1, wherein the multiple-membrane pump is a membrane pump having three or more membranes.
 4. The method for operation according to claim 1, wherein the drive elements are moved at a different stroke frequency.
 5. The method for operation according to claim 1, wherein the drive elements are moved by different drives.
 6. The method for operation according to claim 1, wherein the drives are electric motors, hydraulic or pneumatic cylinders or compressed-air valves. 